I hope this makes sense, if not please feel free to let me know and I'll explain it.
You - 3 from 2 then do 6n=-1
Shanice's rate: 93 / 1.5 = 62 miles per hour
she is 10 miles slower than twice the speed of Brandon
62 +10 = 72
72/2 = 36
Brandon is driving 36 miles per hour
1st ring=$50
2nd ring=$37.50
3rd ring=$25
$50+$37.50+$25 =$112.50 total cost before tax
$112.50 X 1.08=$121.5 total cost and tax
3 X $50 X 1.08=$162 total cost without discount deal
$162 - $121.50 =$40.50 savings